Switch structure



March 19, 1940, B. E- SHAW SWITCH STRUCTURE Filed April 10, 193917206722277"; 412E725 Jfiwa/ 75 Patented Mar. 19, 1940 PATENT oFFIcESWITCH STRUCTURE Burton E. Shaw, Bristol, Ind., assignor to PennElectric Switch 00., Goshen, Ind., a corporation of Iowa ApplicationApril '10, 1939, Serial No. 266,944

7 Claims.

An object of my invention is to provide a switch structure, particularlyadapted for efficient operation of a mercury tube type of switch inresponse to a condition responsive element.

5 Another object is to provide a switch structure including convenientmeans to mount one or more mercury switch tubes for oscillating movementbetween opened and closed positions in response to the conditionresponsive element.

in Another object is to provide means for mounting the mercury switchtube consisting of a pair of U-shaped brackets one being mountedstationarily in the casing of the switch and the other being pivoted tothe first one and in turn supporting a mercury switch tube. The secondbracket being connected by link mechanism to an actuating element foroperation in response to movement thereof.

Still a further object is to provide a magnet :20 cooperating with themercury tube switch to insure quick movement thereof to the opened andclosed circuit positions with the connection between the mercury switchtube and an actuating element therefor including a lost motion connec-23 tion and resilient means biasing the lost motion connection to one ofits limits of movement.

With these and other objects in view, my invention consists in theconstruction, arrangementand combination of the various parts of myswitch structure, whereby the objects contemplated are attained, ashereinafter more fully set forth, pointed out in my claims, andillustrated in the accompanying drawing, in which:

Figure '1 is a front elevation of a switch struc- I :3 ture embodying,my invention. The cover of the switch being removed and-portions of thestructure being broken away and shown in section to illustrate detailsthereof.

Figure 2 is a sectional view on the line 2-2 of Figure l.

Figure 3 is a sectional view on the line 3-3 of Figure 1 and showing abottom plan View of a pair of mercury tube switches of my switchstructure.

4 Figure 4 is a view similar to a portion of Figure 1 showing the switchin open circuit position as compared to closed circuit position as shownin Figure l.

Figure 5 is a similar view of a portion of Figure so 4 showing theswitch at the start of the closing operation.

Figure 6 is an enlarged sectional view on the line 6-6 of Figure 4.

Figure 7 is a similar sectional view on the line 55 1-] of Figure 5; and

Figure 8 is a sectional view as takenon the line 8-8 of Figure 1 andshowing a modified construction.

On the accompanying drawing I have used the reference numeral Ill toindicate a casing and I2 =5 a cover therefor. A condition responsivemeans in the form of a bellows I3 is provided, the head of the bellowshaving an actuating pin [4 extending into the casing Ill. The pin l4coacts with a bell crank lever I5 pivoted at l6.

A range adjusting spring Ila is provided opposing pressure against thehead of the bellows l3. One end of the bell crank I5 is positioned in alimiting slot ll of a bracket [8 while the other end has an opening I 9surrounding a post 20. An adjusting screw 2| is threaded into the postand a spring 22 is interposed between the bell crank l5 and the head ofthe screw 2|. Thepost 20 is provided with a shoulder 23 engaged by thelower end of the spring in the open circuit posi- 2!) tion of the switchas shown in Figure 4.

The spring 22 serves to load the bell crank-l5 when in cut-in positionof Figure 1, but has no effect on the cut-out point of the switchbecause of engagement of the lower end of the spring with 25 theshoulder 23 when in the cut-out position of Figure 4.

A U-shaped bracket 24 is mounted in the casing II] as by screws 25. Thearms thereof carry a pivot pin 26. Oscillatably mounted on the pivot .30pin 26 is a second U-shaped' bracket 21. The U-shaped bracket 21supports a pair of mercury switch tubes S, as shown in Figure 2, a clip28 being riveted to the U-shaped bracket 21 and engaging the switchtubes S under tension to I normally retain them in the desired positionrelative to the bracket 21. r

In Figure 2 I have shown a two tube switch while in Figure 8 Iillustrate modified forms of brackets 24a and 21a for a single tubeswitch. 4.0 The bracket 21a is formed to encircle the single switch tubeS and is made of initially smaller size than the external diameter ofthe tube so that the tube is frictionally held therein. A relativelyshorter pivot pin 26a is shown for the modified form of Figure 8. TheU-shaped bracket 21a has an arm 29 extending therefrom and terminatingin an armature portion 30 bent laterally from the arm. The armatureportion 30 is adapted to cooperate with a magnet 3| which is mounted 59in position in the casing ID by means of a clamp plate 32 and clampscrew 33. The casing is slotted as at 34 so that the magnet 3| can beadjusted upwardly or downwardly to change the inclination of the switchtubes S in their open circuit position of Figure 4. In this position themagnet 3| acts as a stop for the arm 29 by reason of protuberances 35 onthe armature portion engaging the poles of the magnet.

An operative connection is provided between the bell crank I5 and thebracket 21 in the form of a link 36 having an extension 31. Theextension 31 has a portion 38 extended through an opening 39 of thebracket 21 and the extension is somewhat smaller than the diameter ofthe opening. A leaf spring 40 is secured to another lateral extension 4|of the arm 29 and contacts with the upper surface of the portion 38 asshown in Figures 6 and 7. The opening 39 and the portion 38 thereinconstitute a lost motion connection and the leaf spring 40 tends to biasthis connection to the open switch position thereof.

The switches S may be of any desired mercury type. By way ofillustration in Figure 1 the portion of the switch is broken away toshow a metallic casing 42 constituting one electrode of the switch and adisc 43 constituting the other electrode thereof. Within the tube,mercury 44 serves as a means of electrically connecting the terminalstogether. The usual flexible leads 45 extend from the terminals 42 and43.

Practical operation In the operation of my switch structure, when thepressure is low against the head of the bellows l3, the parts willassume the position illustrated in Figure 1 with the mercury 44 bridgingthe terminals 42 and 43 of the switch. An increase in pressure againstthe head of the bellows l3 will move the horizontal arm of the bellcrank l5 downwardly toward the position of Figure 4. During all of thismovement the leaf spring 40 will hold the portion 38 of the linkextension 3'! against the lower edge of the opening 39 as shown inFigure 7. During the last portion of this movement, the magnet 3| willcooperate with the armature 30 to quickly swing the switch S to its openposition as in Figure 4. The magnet, during this last portion of themovement of i the switch, swings the armature and the bracket 21downwardly against the tension of the spring 40 so that the parts willassume the position shown in Figure 6.

When the pressure on the head of the bellows l3 recedes, the link 36will be raised and will first move the portion 38 of the link extension31' from the position of Figures 5 and 7 to the position of Figure 6.This places the leaf spring 40 under additional tension and when theportion 38 engages the top of the opening 39 it will positively move thebracket 2'! thus moving the armature 30 into a weaker magnetic field ofthe magnet 3|. This will effect a quick movement of the switch S towardthe closed circuit position of Figure 1. Thus by means of the armatureand magnet and the lost motion connection I am able to insuresatisfactory movement of the switches S from one position to another.This is particularly desirable where the two switches are to besynchronized for simultaneous opening and closing of circuits whereaswithout the snap action provided by the armature and magnet suchsynchronization is extremely diflicult to obtain.

Some changes may be made in the construction and arrangement of theparts of my device without departing from the real spirit and purpose ofmy invention, and it is my intention to cover by my claimaany modifiedforms of struc:

ture or use of mechanical equivalents, which may be reasonably includedwithin their scope.

I claim as my invention:

1. In a switch structure, a casing, a condition responsive actuatingelement therein, a U-shaped bracket secured to said casing, a pivot pincarried by the arms thereof, a second U-shaped bracket having armspivotally mounted on said pivot pin, a mercury switch tube supported ina loop of said second U-shaped bracket, a lost motion connection betweensaid actuating element and said second U-shaped bracket, a magnetcooperating with said second U.-shaped bracket to bias it to movetowards open switch position and a leaf spring carried by said secondU-shaped bracket and constraining said lost motion connection towardsswitch closing position.

2. In a switch structure, a casing, a condition responsive actuatingelement therein, a bracket secured to said casing, a pivot pin carriedthereby, a second bracket mounted on said pivot pin, a mercury switchtube, a clip secured to said second bracket for mounting said mercuryswitch tube thereon, a lost motion connection between said actuatingelement and said second bracket, a magnet cooperating with said secondbracket to bias-it to move towards open switch position and a leafspring carried by said second bracket and constraining said lost motionconnection towards switch closing position.

3. In a switch structure, a condition responsive actuating element, amercury switch tube pivotally mounted, an actuating element therefor, alost motion connection between said actuating element and said switchtube, an armature connected with said switch tube, a magnet cooperatingwith said armature to bias it to move towards one switch position andthereby tending to move said lost motion connection to one of its limitsand resilient means constraining said lost motion connection towards theopposite limit of its lost motion.

4. Ina switch structure, a casing, a condition responsive actuatingelement therein, a bracket secured to said casing, a pivot pin carriedthereby, a second bracket mounted on said pivot pin, a mercury switchtube, an arm extending from said second bracket and terminating in anarmature, a magnet for cooperation with said armature and tending tobias it toward switch open position, said armature having a protuberancefor contact with said magnet, said second bracket having an openingtherein, a link extending from said actuating element and having aportion in said opening of less size than the diameter of the openingand a leaf spring carried by said second bracket and biasing saidportion toward the side .of said opening engaged thereby normally uponsaid actuating element moving toward switch open position.

5. In a switch structure, a mercury switch tube pivotally mounted, anactuating element for said mercury switch tube, an arm extendingtherefrom and terminating in an armature, a magnet for cooperation withsaid armature and tending to bias it toward one position, said armhaving an opening therein, a link extending from said actuating elementand having a portion in said opening of less size than the diameter ofthe opening, and spring means biasing said portion toward the side ofsaid opening that permits said magnet to draw said armature against thebias of tiltably mounted, an arm extending therefrom and terminating inan armature, a magnet for cooperation with said armature, said armaturehaving a protuberance for contact with said magnet, said arm having anopening therein, means extending from said actuating element and throughsaid opening, said means being of. less size than the diameter of theopening, a leaf spring carried by said arm and biasing said means towardone side of said opening and stationary means biasing said arm to movein a direction in opposition to said leaf spring, said stationary meansovercoming said leaf spring when said arm is on one side of a criticalposition .and being incapable of doing so when said arm is on theopposite side of said critical position.

'7. In a switch structure, a casing, a condition responsive element, anactuating element operated thereby, a mercury switch oscillatablymounted in said casing, an armature movable simultaneously with saidmercury switch, a mag net cooperating with said armature, a lost motionconnection between said actuating element and said mercury switch andresilient means constraining said lost motion connection to one of itslimits of movement, said armature being movable away from said magnetagainst the constraint of said resilient means, said magnet acting as astop for said armature in the open position of. the switch and beingmovable relative to said casing to stop the switch at selectivepositions of inclination of the switch.

BURTON E. SHAW.

